Hello all. You've all helped me in planning my box vegetable garden and now that I am ready to build another question came to mind.

The "box" will really just be a frame 12' x 4' which will sit right on existing grass. I'll put newspaper down on top of the grass and then fill the box with soil. So here's my question re: drainage.

Do you think it's okay to just allow the garden to drain as part of the normal grade of the existing lawn on which it sits, or is it necessary to put some perforated pvc pipe under the soil which lead to drainage holes cut into the frame? I figured the former was fine since it's sitting on top of existing soil and not something like concrete but wanted to be sure. Any thoughts?